Classifications

• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06F—ELECTRIC DIGITAL DATA PROCESSING
  • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
  • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
  • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
  • G06F3/033—Pointing devices displaced or positioned by the user, e.g. mice, trackballs, pens or joysticks; Accessories therefor
  • G06F3/0354—Pointing devices displaced or positioned by the user, e.g. mice, trackballs, pens or joysticks; Accessories therefor with detection of 2D relative movements between the device, or an operating part thereof, and a plane or surface, e.g. 2D mice, trackballs, pens or pucks
  • G06F3/03543—Mice or pucks
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
  • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
  • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
  • G01D5/243—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the phase or frequency of ac
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05G—CONTROL DEVICES OR SYSTEMS INSOFAR AS CHARACTERISED BY MECHANICAL FEATURES ONLY
  • G05G9/00—Manually-actuated control mechanisms provided with one single controlling member co-operating with two or more controlled members, e.g. selectively, simultaneously
  • G05G9/02—Manually-actuated control mechanisms provided with one single controlling member co-operating with two or more controlled members, e.g. selectively, simultaneously the controlling member being movable in different independent ways, movement in each individual way actuating one controlled member only
  • G05G9/04—Manually-actuated control mechanisms provided with one single controlling member co-operating with two or more controlled members, e.g. selectively, simultaneously the controlling member being movable in different independent ways, movement in each individual way actuating one controlled member only in which movement in two or more ways can occur simultaneously
  • G05G9/047—Manually-actuated control mechanisms provided with one single controlling member co-operating with two or more controlled members, e.g. selectively, simultaneously the controlling member being movable in different independent ways, movement in each individual way actuating one controlled member only in which movement in two or more ways can occur simultaneously the controlling member being movable by hand about orthogonal axes, e.g. joysticks
  • G05G2009/0474—Manually-actuated control mechanisms provided with one single controlling member co-operating with two or more controlled members, e.g. selectively, simultaneously the controlling member being movable in different independent ways, movement in each individual way actuating one controlled member only in which movement in two or more ways can occur simultaneously the controlling member being movable by hand about orthogonal axes, e.g. joysticks characterised by means converting mechanical movement into electric signals
  • G05G2009/04755—Magnetic sensor, e.g. hall generator, pick-up coil

Definitions

• This invention relates to an apparatus fo monitoring at least one of the rotational movement and the orientation of a substantially spherical body.
• the invention has particular, but not exclusive, relevance to a man-machine interface in which a user inputs information to a machine by varying the orientation of a substantially spherical body.
• a man-machine interface is a ball tracking device in which a user directly moves a ball and one or both of the direction and the speed of rotation of the ball conveys information to the associated machine.
• a man-machine interface is a computer mouse in which a ball is mounted in a housing with part of the ball protruding through the housing to contact a surface on which the computer mouse rests. A user holds the housing and drags the mouse across the surface causing the ball to rotate, and one or both of the direction and the speed of rotation conveys information to the associated machine.
• a further example of such a man-machine interface is a joystick in which a ball-and-socket joint is formed at one end of a lever, and the user moves the lever to cause rotation of the ball in the ball-and-socket joint, one or both of the direction and the speed of rotation conveying information to the associated machine.
• a common mechanism for monitoring the orientation of a spherical body utilises a pair of orthogonally arranged shafts which contact the spherical body so that they rotate as the spherical body rotates.
• the rotation of each shaft is measured using a respective optical sensor in which a beam of light is broken by paddles attached to each of the shafts.
• the resulting light pulses are electronically registered and processed to provide orientation information to the host machine.
• ingress of foreign matter such as dirt can interfere with the friction characteristics between the spherical body and rotating shafts, and can also obscure the light beams used by the optical sensors.
• a sensor in which an inductive sensing arrangement is used to monitor the orientation of, or rotational movement of, one or more resonant circuits mounted in or on a spherical body.
• the inductive sensor comprises a transmit aerial and a receive aerial which are isolated from the external environment by a membrane to prevent the ingress of foreign matter to the cavity housing the electronics associated with the man-machine interface.
• the membrane is impermeable.
• Figure 1 schematically shows a side view of a ball tracking device
• Figure 2 is a circuit diagram of a resonant circuit which forms part of the ball tracking device illustrated in Figure 1;
• Figure 3 is a sectional view through the centre of a ball forming part of the ball tracking device illustrated in Figure 1;
• Figures 4A to 4E are schematic plan views of windings deposited on a printed circuit board which forms part of the ball tracking device illustrated in Figure i;
• Figure 5 schematically shows electronic circuitry associated with the ball tracking device illustrated in Figure 1
• Figure 6 schematically shows a side view of an alternative ball tracking device to the ball tracking device illustrated in Figure 1;
• Figure 7 schematically shows a side view of a computer mouse
• Figure 8 schematically shows a side view of a joystick
• Figure 9 schematically shows a side view of an alternative joystick to the joystick illustrated in Figure 8 ; and Figure 10 schematically shows a side view of a second alternative joystick to the joystick illustrated in Figure 8.
• the ball tracking device includes a ball 1 which rests on three point supports 3a, 3b, 3c which protrude from a planar impermeable membrane 5.
• the planar membrane 5 is positioned in the X-Y plane.
• the point supports 3 prevent lateral movement of the ball 1 relative to the membrane 5, but allow the ball 1 to rotate in all directions under the influence of a user.
• the ball 1 includes three resonant circuits 9a, 9b and 9c which are generally arranged in mutually orthogonal planes which intersect at the centre 11 of the ball 1.
• the membrane 5 separates the ball 1 from a printed circuit board (PCB) 7 on which are formed a transmit aerial and a receive aerial (not shown in Figure 1).
• the point supports 3 maintain the centre 11 of the ball 1 above a fixed point 13 on the PCB 7.
• the transmit aerial is connected to an excitation signal generator (not shown in Figure 1) which supplies electrical signals to the transmit aerial to generate a magnetic field.
• the generated magnetic field induces resonant signals in one or more of the resonant circuits 9 which vary in accordance with the orientation of the ball 1, and these resonant signals in turn induce a sensed signal in the receive aerial on the PCB 7.
• the receive aerial is connected to a signal processor (not shown in Figure 1) which processes the sensed signal from the receive aerial to determine the orientation of the ball 1.
• impermeable membrane 5 prevents the ingress of foreign matter into the cavity holding the PCB 7, the excitation signal generator and the signal processor, without interfering with the electromagnetic coupling between the transmit aerial, the receive aerial and the resonant circuits 9.
• FIG 2 shows a circuit diagram of one of the resonant circuits 9.
• each resonant circuit 9 includes a coil 21 whose ends are connected together via a capacitor 23.
• the resonant circuit 9 has an associated resonant frequency.
• each of the resonant circuits 9 has a respective different resonant frequency between 1MHz and 3MHz.
• the ball 1 is formed by a spherical plastic body 31 in which three orthogonal circumferential grooves 33a, 33b and 33c, are formed.
• Each of the resonant circuits 9 is formed by ten turns of insulated copper wire 35a, 35b and 35c within a respective circumferential groove 33, with the ends of the wires soldered to respective terminals of a capacitor.
• the wound assembly is then potted and sealed by a covering coat 37 formed of polymer epoxy.
• the PCB 7 is generally square in shape with the fixed point 13, above which the centre 11 of the ball 1 is positioned by the point supports 3, substantially located at the centre of the PCB 7.
• five windings are formed on the PCB 7, four of which form the transmit aerial and the remaining one of which forms the receive aerial. These five windings are illustrated in Figures 4A to 4E respectively.
• the transmit aerial is formed by two pairs of excitation windings.
• Figures 4A and 4B show the first pair of excitation windings, hereafter called the X_sine coil 41 and the X_cosine coil 43 and figures 4C and 4D show the second pair of excitation windings, hereafter called the Y_sine coil 51 and the Y_cosine coil 53.
• the X_sine coil 41 is formed by a conductive track which generally extends around the periphery of the PCB 7 apart from a cross-over point half way along the PCB 7 in the X-direction, at which the conductive track on each edge of the PCB 7 crosses to the corresponding opposing edge of the PCB 7. In this way, effectively a first current loop 45a and a second current loop 45b are formed.
• a signal is applied to the X sine coil 21
• current flows around the first current loop 45a and the second current loop 45b in opposing directions, and a magnetic field is generated which passes through the Y-Z plane including the point 13 generally perpendicularly.
• the X_cosine coil 43 is formed by a conductive track which generally extends around the periphery of the PCB 7 apart from two cross-over points, located one-quarter and three-quarters of the way along the PCB 7 in the X-direction respectively. In this way, three loops 47a, 47b and 47c are formed of which the outer loops 47a and 47c are approximately half the size of the inner loop 47b.
• a signal is applied to the X_cosine coil 43, current flows in one direction around the outer loops 47a and 47c and in the opposite direction around the inner loop 47b.
• the magnetic field generated by the current flowing around the inner loop 47b has an opposite polarity to the magnetic field generated by the current flowing around the outer loops 47a and 47c, generating a magnetic field which passes generally perpendicularly through the X-Y plane including the point 13.
• the Y_sine coil 51 and the Y_cosine coil 53 correspond to the X_sine coil 41 and X_cosine coil 43 rotated through 90° respectively.
• ⁇ y is the angle subtended between the plane of the resonant circuit 9 and the Y-direction
• the electromagnetic coupling between the Y_sine coil 51 and the resonant circuit is proportional to sin ⁇ y and the electromagnetic coupling between the Y_cosine coil 53 and the resonant circuit is proportional to cos ⁇ y .
• the receive aerial is formed by a sensor winding 61 which extends around the periphery of the PCB 7.
• the layout of the transmit aerial and receive aerials is such that each excitation winding induces plural current components in the sensor winding 61 which cancel out so that substantially no sense current is generated by direct electromagnetic coupling between the transmit aerial and the receive aerial.
• Using such balanced excitation windings has the further advantage that emissions from the excitation windings diminish with distance at a faster rate than for a single planar winding. This allows larger drive signals to be used while still satisfying regulatory requirements for electromagnetic emissions.
• each of the resonant circuits 9 is sequentially interrogated by applying excitation signals at the resonant frequency of the interrogated resonant circuit so that resonant signals are induced in the interrogated resonant circuit but not in the other resonant circuits. Further, during interrogation of a resonant circuit the angles ⁇ x and ⁇ y are sequentially determined by sequentially addressing the first and second pairs of excitation windings. From these measurements, rotational movement of the ball 1 around the x-axis and y-axis can be monitored.
• the excitation signal generator 71 generates an in-phase signal I(t) and a quadrature signal Q(t) at respective different outputs.
• the in-phase signal I(t) is generated by amplitude modulating an oscillating carrier signal having a carrier frequency f 0 , which is substantially identical to the resonant frequency of the interrogated resonant circuit 9, using a first modulation signal which oscillates at a modulation frequency f lf which in this embodiment is 3.9kHz.
• the in-phase signal I(t) is therefore of the form:
• I(t) A sm ' 2 ⁇ f ⁇ t cos2 ⁇ f 0 t (1)
• the quadrature signal Q(t) is generated by amplitude modulating the oscillating carrier signal having carrier frequency f 0 using a second modulation signal which oscillates at the modulation frequency f, with the second modulation signal being ⁇ /2 radians (90°) out of phase with the first modulation signal.
• the quadrature signal Q(t) is therefore of the form:
• the in-phase signal I(t) is applied to the X_sine coil
• the total magnetic field generated has components corresponding to the X_sine coil 41 and the X_cosine coil 43.
• the electromagnetic coupling Ci between the component of the total magnetic field corresponding to the X_sine coil 41 and the interrogated resonant circuit 9 varies sinusoidally with ⁇ x according to the function:
• the electromagnetic coupling C 2 between the component of the total magnetic field corresponding to the X_cosine coil 43 and the interrogated resonant circuit 9 also varies sinusoidally with ⁇ x , but with a phase difference of ⁇ /2 radians (90°) from the electromagnetic coupling C 17 giving:
• the resonant current I res induced in the interrogated resonant circuit is formed by a first component from the X_sine coil 41 and a second component from the X_cosine coil 43, with the magnitudes of the first and second components varying with the angle ⁇ x .
• the induced resonant current I res is of the form:
• the induced resonant current I res induces a proportional sense current in the sense coil 61 which is input to the signal processor, which in this embodiment is formed by a demodulator 73, a phase detector 75 and an angle calculator 77.
• the demodulator 73 removes the component of the sense current at frequency f 0 , leaving a demodulated signal at the frequency fj . .
• the demodulated signal is input to the phase detector 75, which measures the phase of the demodulated signal relative to a reference phase, and outputs the measured phase to the angle calculator 77 which determines the angle ⁇ x .
• the excitation signal generator and the signal processor used in this embodiment are described in more detail in UK Patent Application GB 2374424A, whose contents are incorporated herein by reference.
• the angle ⁇ y is measured by switching the outputs I(t) and Q(t) of the excitation signal generator 71 from the X_sine coil 41 and X_cosine coil 43 to the Y_sine coil 51 and Y_cosine coil 53 respectively.
• the interrogated resonant circuit is changed by switching the frequency f 0 to match the resonant frequency of one of the other resonant circuits.
• a ball tracking device in which rotational movement of a ball by a user is monitored by a machine.
• a ball tracking device is commonly used in conjunction with a display to control the movement of a cursor over the display.
• the cursor once the cursor has been positioned over a desired portion of the display surface (for example over an icon associated with a computer program) , typically the user activates a switch to indicate a selection.
• FIG. 6 A second embodiment will now be described with reference to Figure 6 in which a switching device is incorporated within the ball tracking device.
• a switch 81 is mounted on the PCB 7 and protrudes into one of the point supports 3.
• the switch 81 is a normally-open spring loaded switch and the point support 3c is made of a resilient material which, when a user presses down hard (i.e. more firmly than when varying the orientation of the ball 1), deforms so that the contacts of the switch 81 close indicating a user selection.
• the first and second embodiments describe ball tracking devices in which a user directly manipulates the ball 1.
• FIG. 7 A third embodiment of the invention will now be described with reference to Figure 7 in which the ball tracking device is incorporated within a computer mouse.
• components which are identical to corresponding components of the first embodiment have been referenced with the same numerals and will not be described in detail again.
• the ball 1 is mounted within a housing 91 along with the PCB 7.
• a portion of the ball 1 protrudes out of the housing 91, and in common usage this protruding portion of the ball 1 rests on a surface 93 so that when a user holding the housing 91 drags the computer mouse over the surface 93, the ball 1 rotates.
• the rotational movement of the ball 1 is sensed using the transmit aerial and receive aerial on the PCB 7 in the same manner as in the first embodiment.
• the PCB 7 is isolated from the ball 1, and therefore the exterior of the housing 91, by an impermeable membrane.
• the excitation generator and the signal processor are located in a host device which is connected to the computer mouse by a cable (not shown in Figure 7) .
• the ball tracking device of the present invention can also be incorporated within a joystick.
• Components in Figure 8 which are identical to corresponding components in the first embodiment have been referenced with the same numerals and will not be described in detail again.
• the ball 1 is physically connected to a lever 101 (i.e. the joystick) which is manipulated by a user.
• the ball 1 is rotatably mounted within a housing 103 to form a ball-and-socket joint, and the PCB 7 is fixed relative to the housing 103.
• the orientation of the ball 1 varies and this change in orientation is detected using the transmit aerial and the receive aerial formed on the PCB 7 in the same manner as the first embodiment.
• the ball 1 is not required to have complete freedom of rotation because the lever 101 moves only within a restricted solid angle. This allows a single resonant circuit 9 to be used because it can be ensured that the orientation of this resonant circuit does not become orthogonal to the plane of the PCB 7.
• FIG. 9 A fifth embodiment of the invention will now be described with reference to Figure 9 in which a single resonant circuit is formed on a piece of printed circuit board which moves with the ball 1.
• components which are identical to corresponding components in the fourth embodiment have been referenced with the same numerals and will not be described in detail again.
• a lever 111 passes through the centre of a ball 113 which is rotatably mounted within the housing 103.
• One end 115a of the lever projects outwardly of the housing 103 so that a user is able to manipulate the lever 111.
• the other end 115b of the lever 111 projects a short distance out of the ball 113, and a printed circuit board (PCB) 117 is fixed to this end 115b with the plane of the PCB 117 approximately parallel with the plane of the PCB 7 when the lever 111 is generally perpendicular to the plane of the PCB 7.
• a single resonant circuit (not shown in Figure 9) is formed on the PCB 117. It will be appreciated that as the ball 113 rotates, the position of the resonant circuit on the PCB 117 above the transmit aerial and the receive aerial formed on the PCB 7 will vary, and this position is measured using equivalent processing to that used in the previous embodiments.
• FIG. 10 A sixth embodiment of the invention will now be described with reference to Figure 10 in which a switch is added to the joystick arrangement of the fifth embodiment.
• Components of the sixth embodiment identical to corresponding components of the fifth embodiment have been referenced with the same numerals and will not be described in detail again.
• a normally open spring-loaded switch 121 is mounted to the end 115a of the lever 111 projecting out of the housing 103.
• the switch 121 is connected by wiring 123 through the lever 111 to the printed circuit board 117.
• two resonant circuits are formed on the PCB 117.
• the first of the two resonant circuits is identical to that of the fifth embodiment and is used to determine the orientation of the ball 113.
• the second resonant circuit includes the switch 121 so that normally the second resonant circuit is open and does not resonate. However, when the user presses the switch 121, this second resonant circuit closes and resonates in response to an electric signal at its resonant frequency being applied to the transmit aerial on the PCB 7. In this way, by periodically applying an electric signal at the resonant frequency of the second resonant circuit, whether or not the switch 121 has been depressed can be continuously monitored.
• the joysticks of the fourth to sixth embodiments can also incorporate biasing means for biasing the lever 111 to a centre position in which the lever 111 is perpendicular to the PCB 7.
• biasing means for biasing the lever 111 to a centre position in which the lever 111 is perpendicular to the PCB 7.
• magnets could be used to provide magnetic centring of these joystick arrangements.
• the orientation of the ball within the joystick is determined using a resonant circuit which is mounted on a printed circuit board mounted to the outside of the ball.
• the resonant circuit could be formed by a conductive track deposited on another type of planar substrate.
• the resonant circuit could be formed by forming a coil, connected at each end to a terminal of a capacitor, deposited directly on the surface of the spherical body.
• resonant circuits incorporating small planar coils are spaced around the surface area of the spherical body.
• these resonant circuits could be embedded under the surface of the spherical body.
• the resonant circuits mounted in or on the spherical body are passive resonant circuits.
• active resonant circuits incorporating an amplifier for amplifying the resonant signals, could be used.
• Such active resonators would, however, require the spherical body to include a power source.
• a user depresses a switch in order to make a selection.
• a user may make a selection by pushing the spherical body closer to the transmit and receive aerials, which results in a larger signal being induced in the receive aerial.
• the switch opens and closes a resonant circuit which is separate from the resonant circuit which is used for determining the orientation of the ball.
• a single resonant circuit could be used in which the ends of a coil are connected to respective terminals of a first capacitor, and a serial combination of a switch and a second capacitor are connected in parallel with the first capacitor.
• the switch when the switch is open the resonant circuit has a first resonant frequency, whereas when the switch is closed the resonant circuit has a second resonant frequency different from the first resonant frequency. Therefore, by applying electrical signals substantially at the first and second resonant frequencies to the transmit aerial, the orientation of the ball can be monitored and whether or not the switch is open or closed can be determined.
• the switch may be replaced by a movable piece of permeable material (e.g. ferrite) placed in proximity to at least part of the winding forming the resonant circuit. Movement of the permeable material by the user causes a change in the resonant characteristics, for example resonant frequency or quality factor, which can be measured. Therefore, a user is able to make a selection by moving the permeable material.
• a movable piece of permeable material e.g. ferrite
• lateral movement of the spherical body is prevented by a physical mounting means.
• the spherical body could be supported by jets of air.
• point supports are used to support the ball.
• roller bearings could be used to support the ball.
• the ball is removably mounted so that it can be used by a user as part of an access control system.
• the respective resonant frequencies of the resonant circuits within the balls are varied from ball to ball so that each user has a ball with unique resonant properties .
• the man-machine interface device performs an initialisation routine in which excitation signals at all possible resonant frequencies are applied to the transmit aerial, and from the signals received by the receive aerial the resonant frequencies of the ball currently being used are determined. In this way, the man-machine interface device is able to identify the user.
• the spherical body forms part of a man-machine interface in which a user varies the orientation of the spherical body to input information to a machine.
• the invention is generally applicable to any device in which the orientation and/or movement of a spherical body conveys information.
• an attitude sensor frequently employs a ball, weighted at one pole, supported by a fluid so that as the attitude of the aircraft varies the ball remains in a fixed position with respect to ground. Therefore, by mounting the transmit aerial and the receive aerial so that they move with the aircraft, the attitude of the aircraft can be detected by measuring the relative orientation between the ball and the transmit and receive aerials.

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• 2003
  • 2003-02-05 JP JP2003566488A patent/JP4249628B2/ja not_active Expired - Fee Related
  • 2003-02-05 US US10/503,362 patent/US7554527B2/en not_active Expired - Fee Related
  • 2003-02-05 WO PCT/GB2003/000495 patent/WO2003067181A2/en active Application Filing
  • 2003-02-05 AU AU2003208397A patent/AU2003208397A1/en not_active Abandoned
  • 2003-02-05 EP EP03706685A patent/EP1472595A2/de not_active Withdrawn
  • 2003-02-05 CN CN03807750.7A patent/CN1647018B/zh not_active Expired - Fee Related

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